Power Flush

Are your radiators cold at the bottom, or do they have cold spots in specific areas? Does the system not heat up as well as it used to or maybe some radiators do not heat up at all? Ever heard the phrase Power Flush? Fear not! Resolve Gas Services are experts in power flush Liverpool.




Quick Understanding of What’s Happening


Over time, debris such as rust from the radiators, flux and/or solder left behind after installation builds up in your central heating system. This is commonly known as BLACK SLUDGE. If not removed or treated this will inevitably lead to restrictions within the radiators, pipework and boiler and it will lead to premature component and system failure. In a lot of cases, it causes complete blockages, meaning the hot water cannot circulate around the heating system.

It also means higher heating bills, increased levels of carbon emissions, costly maintenance call-outs and ultimately reduced central heating system lifespan.

What is the black sludge in radiators?


When taking a radiator off the wall for decorating, have you ever wondered what is the black sludge in it? Heating engineers refer to the black sludge, which has a resemblance to oil, as ‘magnetite’.

Magnetite is a build-up of rust that has fallen from the inside of the radiator. Black sludge is iron oxide and it also has small sharp particles inside. It also comes from cast iron heat exchangers and circulating pumps. If not managed, this will eventually become so thick that it will stagnate and lead to the restrictions / blockages we mentioned earlier.


Engineer’s Tip:


If you notice small changes within the heating system, such as radiators warming when they should be turned off or radiators warming whilst running hot water then this is a sign that magnetite is forming within the system.

Magnetite even attaches to surfaces within components such as diverter valves. This then allows water to pass round circuits that would normally be closed depending on which demand (heating or hot water) was in operation.

The magnetite metal particles are also attracted to the circulating pump. This is due to the fact the pump winding creates a magnetic field. Once affected, the pump often goes weak or “sluggish” and will also seem noisy.

Of course, all these issues can be rectified without the need for a power flush Liverpool, however, this would be ultimately “masking” the underlying issue.

Another symptom that the central heating contains magnetite is if you have to bleed the radiators frequently. This is the result of a chemical reaction which causes the system to “gas up”.

We commonly hear customers inform us that they have to bleed the ‘air’ from the radiators more often than usual. In actual fact what the customer is most likely removing is hydrogen. This hydrogen gas is caused by the rusting and corrosion process. It can sometimes also give off a foul “egg” like smell.


How do I bleed all the radiators in the house?



If your radiator is cold at the top and hot at the bottom then this is usually ‘air’. You can simply bleed the ‘air’ from any affected radiator by following the steps below.

  • Turn off the heating
  • Place a protective dust sheet below the radiator you want to bleed. It is also handy to have a jug or bowl nearby to catch any water that escapes
  • Take the radiator bleed key and attach it to the bleed point
  • Open the bleed point until all the ‘air’ has been removed from the radiator.
  • Close the bleed point and check for leaks

If you would like to see a demonstration then watch the video below…




Radiator sludge build-up


When a heating system has not been cleaned out or no inhibitor has been added a corrosion process takes place. Water reacts with the steel radiators and dissimilar metals.

Particles of rust detach from the radiator and sink to the bottom of the vessel. Once blocked, the hot water cannot travel to the bottom of the radiator and simply finds the easiest route through the radiator, as demonstrated in the graphic below.

The magnetite tends to stagnate during periods of non-use, such as over the summer months. Once the magnetite has stagnated, it is really difficult to remove.

So what’s the solution?

How to flush a radiator in the house?

The best way for a customer to remove black sludge from a radiator is to disconnect the radiator from the system and flush it outside.

However, this is not always practical and comes with risk such as staining carpets/flooring should the customer spill any black sludge during the removal process.

Here are some handy tips, should you wish to do this:

Electrically isolate the central heating by switching it off at the fuse spur.

Completely drain down the central heating system at a suitable drain off point. For conventional systems, you may need to turn the cold main supply off or isolate the water entering the feed & expansion tank, usually within the loft space.

Once drained down, thoroughly protect the floor along the whole route to outside. We recommend using a dust sheet with a protective coating on the base. This prevents water / black sludge penetrating through the dust sheet.

Disconnect the valves at either side of the affected radiator. Have a small tray (such as an oven roasting tin) nearby to catch any small drips of water.

Close the bleed point at the top of the radiator.


Engineer’s tip:


Lift the radiator off the brackets and immediately turn it upside down. This will minimise the risk of spilling black sludge due to the open ends now being at the top!

Place your thumb over the open ends and now take the radiator outside.

It’s best practice to empty any remaining black sludge down any waste drain or on the lawn if necessary. Give it a good shake!

With the radiator in the upright position use a wooden or rubber mallet and give it a firm tap. Concentrate on the area that would be at the bottom.


Now flush the radiator with mains water

Attach a garden hose to the tail of the radiator valve and secure with a 1/2 inch jubilee clip.

Turn on the water at full bore and whilst flushing, use the mallet to give a firm tap, again concentrating on what would be the base of the vessel.

Once you are happy that the black sludge has been removed, drain the radiator down and re-install it.

You should now close the drain down point, check to make sure all bleed points are closed.

Now fill the central heating system. Bleed all radiators and check for leaks.

If you would like further assistance then please call 0151 558 1999.



Professional Power Flush Liverpool




According to Norstrom Power Flush technical department, a manual cold mains flush will only remove between 10-15% of magnetite. Considering the effort needed to complete a cold mains flush, the results are potentially under-whelming. Why waste time and money knowing the end result will be unsatisfactory or for less than the desired result?


By using a professional power flush machine, around as much as 95% of the magnetite will be removed from the central heating system.


Resolve Gas Services use a top of the range Norstrom PROFLUSH thermal machine for power flushing Liverpool. The end results are truly fantastic.


The Norstrom Proflush Thermal Professional System is regarded as one of the best power flush machines currently on the market.


The Proflush machine allows us to operate at temperatures up to 85ºC, the highest rating in the industry! This means that we can utilise the boiler for hot water during the power flush Liverpool. However, even more crucially, it means that the chemicals we use are more effective than if they are used on a cold flush.


Boiler not working?

What if the boiler is non-operational? This is not a problem for Resolve Gas Services as we use the Thermal version of the machine. This is an electrical element, much like an immersion heater in a water cylinder. We can heat the water up before we start the flush, again making our power flush Liverpool more effective than all other machines used by other companies.


By heating the chemicals we use for the flush, it means that they work more quickly and therefore we GUARANTEE a more thorough and effective power flush Liverpool. Every 10℃ increase in water temperature means that the chemicals work three times faster. This is fantastic.


Our professional power flush machine operates at an impressive flow rate of 150 litres per minute. This is extremely beneficial due to its high velocity of water travelling through the system. However, when you consider that our machine also has a reverse flow feature, this allows us to dislodge any tough stagnated magnetite. Great!


With our professional machine, we can flush up to 40 radiators over a 3 story house, all at the same time!


The average three-bedroom house with 8-10 radiators can be flushed in as little as 4.5 hours*. We can achieve these results when flushing at a temperature between 72-76°C. Our chemicals are working faster and our flushing procedure is more effective.


*Figures according to Norstrom. Please note that Resolve Gas Service’s are in no hurry to flush the system. We are on site until we are satisfied with the results.


Chemicals Used in Power Flush Liverpool




Resolve Gas Services only use premium quality system cleaning chemicals when carrying out a power flush Liverpool. Our aim is to remove as much black sludge from the central heating system as possible. We invested in top of the range equipment to do the job properly, so we refuse to use cheap, non-effective cleaning chemicals.




The chemicals that Resolve Gas Services use are Non-hazardous, Non-toxic and also Biodegradable. It is important to be clear that we will not just dispose of used chemicals down the drain, we are conscientious about the work we do. More on this on our Environmental page.



Adey MagnaClense® to support Power Flush



Adey MagnaClense® is a RapidFlush filter. The unit comprises of two giant magnets that the water passes through whilst being flushed. As the black sludge passes through the canisters the magnets attract the magnetite ensuring it is removed on the first pass!


Let’s see the benefits of the Adey Magnaclense® and how it works.



Resolve Gas Services use the Adey Magnaclense® in conjunction with the Norstrom Professional Proflush at the same time. This ensures we are being as productive as possible whilst we are on site.


Flir ONE Pro assistance!


Most people have never heard of Flir let alone Flir ONE Pro! So what is it? Well, Flir One is a thermal imaging camera that we use on site to have an in-depth look of what is happening within the central heating radiators, boiler and pipework. It allows our engineers to quickly identify areas of concern that would not normally be visible to the naked eye.

Other power-flush companies walk around the central heating system, just feeling the radiator with their hand. Is that a reliable way of proving technically what the issue is? We think not.

Resolve Gas Services invested in this technology to help and assist us whilst carrying out a power flush Liverpool. It is a fantastic piece of equipment that uses high and low gain modules to clearly identify hot and cold spots within a heating system. This then allows us to really concentrate on these areas, rather than waste time in areas that are not as affected by black sludge.

Magnetic System Filter

Once Resolve Gas Services are happy with the power-flush result we would strongly recommend having a magnetic system filter installed. This ensures long-lasting protection for your central heating system, boiler and components.


A magnetic system filter is professionally installed to the pipework below the boiler. As excellently demonstrated in the video below, the magnet collects any black sludge that is produced, protecting the boiler for years to come.

We offer a 10 YEAR WARRANTY on all Adey Magnetic System filters installed by Resolve Gas Services Limited.


Please call us for a quote 0151 558 1999.

Job report for a power flush


Each time we carry out a professional power flush Liverpool, our engineers will provide you with a detailed report for your safe-keeping. Resolve Gas Services will also keep a copy of the report on file should you need a replacement copy.

The report will clearly demonstrate the benefits of the power flush Liverpool procedure. Using a Flir One thermal imaging camera, we can accurately record temperatures before and after the flush.


Power Flush Aftercare

Just because our engineer has left the site, it does not mean our job ends there. We now provide you with a fantastic aftercare service. This may just be to provide you with some useful advice over the telephone. We will, however, endeavour to look after your system for as long as you require.

Resolve Gas Services are happy to attend annually to clear out any magnetic system filters we may have professionally installed. We may service the boiler whilst we are on site too.

Rest assured Resolve Gas Services’ number one aim is to provide a first-class, unrivalled service to our customers. We treat each customer’s home like it is our own.

If you would like to know more or arrange a quote please call 0151 558 1999.


Frequently Asked Questions


Q. How long does a power flush Liverpool take?

A. Generally, we should complete a thorough flush within a day. We have flushed systems in 4-5 hours before, however the emphasis is purely on getting it right. This means we stay late if we have to!

Q. Will my property be protected for damage?

A. Absolutely! We use plenty of dust sheets, carpet protectors and also plastic sheeting when we power flush Liverpool. Our machine also sits inside a purpose-built secondary bund tank so should the machine leak or overflow, it’s contained within the tank.

Q. How much does it cost to power flush Liverpool?

A. Prices start at £247. This includes the hire of the equipment, the chemicals plus an expert engineer to complete the flush.

Q. How often should you flush your heating system?

A. We aim to flush it once. We offer fantastic advice on how to protect the system moving forward.

Should the system, for whatever reason, need flushing again, we would do this free of charge.

We also offer a 2-year warranty on all power flush Liverpool.

Q. Can a power flush cause leaks?

A. Although very rare, there is always a risk that a power flush could cause a leak. There are several reasons why a system leaks during the process. The main reason being the increase in water velocity and pressure.

A power flush machine’s pump is considerably bigger than a standard circulating pump you will have on your heating system. The larger pump increases the water velocity travelling through the system. It could also increase the pressure within a gravity-fed system up to levels that the system has not operated at before.

So yes, there is a very slight risk, but not one that should put you off because, as we say, it is very rare!